Electric amplifier.



H. C. EGERTON. ELECTRIC AMPLIFIER.

APPLICATION FILED AUG. 15. I914.

Patented Dec. 5, 1916. 4 SHEETS-SIIEET I 1 my/mm H, c. EGEHTON. ELECTRIC AMPLIFIER.

I APPLICATION FILED AUG..I5, I9I4. I 1,207,384. Patented Dec. 5,1916.

4 SHEETS-SHEET 2.

Wfinesss:

H. C. EGERTON.

EHICTRIC AMPLIFIER.

APPLICATION FILED AUG. 15. 1914.

1,207,384. Patented Dec. 5,1916.

4 SHEETS-SHEET 3- Affy.

unrrnn scin'iss rn rnuyr OFFIC 11mins c. nsneron, or PASUAIO, new EnsEY, ASSIGNOB, BY MESNE ASSIGNMENTS, r WESTERN nLnoTmc ooiurnnr, INCORPORATED, A CORPORATION on NEW YORK.

ELECTRIC AMPLIFIER.

ll iyh g llf Specification of Letters Patent.

Patented Dec. 5, 1916. plicetion filed August 15, 1914. Serial No. 856,971. I

To all whom e113 may concern and in order to prevent singing of the em plifier these magnet windings are connected to have a differential eiiect with respect to the" armature so that chnnges in this current have no eiiect upon the armature, which is, however, actuated-inresponse to currents-in another set of windings elsoupon the same ceive the current to be amplified, are, dis

Be it known that I, HENRY J. EcEu'roN, posed upon the outer arms of the core, but a citizen of the United States, residing ct are so wo'undthet variations in the current lasseic', in the county of Pussuic and Stuto received will tend tostrengthen one of the 5 of New Jersey, have invented certain new outer'poles and weaken the other, and in end useful Improvements in Electric Ainpli this manner cause the armature to be vifiers, of which the following is a full, clear, hinted. 1 concise, and exact description. The transmitter element preferably com- Tliis invention relates to electric umpli prises two resistance-varying mediums, both 10 fiers of the type used, for example, in enactuated by the single 'arnieture and elec-- nouncing systems to receive and transmit trio-ally connected to give What has been with increased intensity electric currents of culled a fpush and pull effect. In order to 6 5 telephonic and musical frequencies, and provide an efiective radiation of heat, I more purticulu-rly it relates-to a type of am preferably mount the metallic cups of these i5 plifier in which an. clectroniaignet receiving transmitter elements in actual contact with the. current to be amplified ucts upon an a substantial metal base, end the movable arr-nurture which. serves to vibrate a resistelements, which are carried upon the armaunce-i 'aiyingor transmitter element. ture lever, are insulated from said armature The objects of the iiiivcntion are, first, to lev'cr'and from each other. 20 provide an improved magnet system-Where Where it is desired to install a. nuinbe by increased sensitiveness of the amplifier loud 'speuking-telephones forannouncing nc be secured; second, to provide an l-Il'h purposes, usually the most convenient source proved structure and mounting for the of currentis an ordinary lighting circuit; transmitting elements which will eliectively end-a turther feature of my invention con- 25- radiate the'hentgeneruted in the resistance sists in an arrangement such that the ener--- varying medium; and third, to provide n gizing circuits including the energizing improved organization of circuits andsppw magnet windings of the several. amplifiers, 'zi'tusby means of which a. number ofeiir' are connectedinser-ies', soithzrtnthey serve'as plifiers may be conveniently operated fromprotecting resistances for'ea'ch other,-- while so any available source ofdirect current, which at the same time, efieotiiielysupplying difis particularly cles" able for installations of ferent groups oftelephone receivers. this nature. The invention will be more particularly .In the magnet system of my improved described, 21nd further. features thereof amplifier, instead oi the usual permanent pointed out in conneetionwith the acconp- 35 magnet. an iron core is magnetized by wind pnnying drawings, in which ings which are connectedin the semegcir- Figure .1 is avertical cross-sectional View cuit which feedsthetransmitter elements, of an amplifier incorporotingthe improve- 9? merits of this invention; Fig, 2is a horizontal section of the essential elements-of the amplifier taken a. 'ne 2 -2 ofzFig- 1; Fig. 3 is another view of the. semethk'en I elongline-3-3 of Fig: 1","I ig. 4- showsinenlarged form a, deteiljof the motor or re ceiver element of the einlplifier 'lli 5 'sliowsj 45 core. The magnetizing windings also in an enlarged form, a. detail of t e.gene'r--- i 1 connected sofajsto he" rum-inductive with ntor ortrunsmitter'element of the amplifie respect to the actuating windings. Figs. 6 and 7 show, in }:ierspecti e, contact The core is preferably lisped, and) the and supporting meansfor remo ably-moun energizing windings ere srren'gedlto mag ingthe amplifiers in questionon a panel:

50 notice the outer arms of: the core to the some board and for zissoeiating mplui'ality oifthepolarity.- upon or'edgaeent to the control arm 0 the .oormenduthe actuating windings, whic re- The armature is centrallyp'i *oted 4 ferent novel-circuit arrangements which may said amplifiers together-in a single system;

Figs. 8, 9, 10 and ll'show schemeticallydif to'give to the vibrating system of the amplilicr the required elasticity, and their tension is normally adiu sted so as to maintain substantially equal air-gaps between the ends ofithe armature 2 1- and the poles 35. Armature 24 may be provided with longitudinal slots 46 .to decrease the eddy-cur rent losses therein.

As a combined means for mounting the amplifier and connectin it in circuit, the base 1 carries terminal buttons 47 and d8 insulated therefrom by bushings l9 of hard rubber and washers 50 of mica, buttons 4t? and 48 being held iii-place by nuts 51 on the threaded shanks 52 of said buttons, said nuts also clamping in place soldering terminals 53. Buttons 48 differ from -l-7 in that they have necks 5i and heads 55 adapted to fit-into button slots 56 in, channeled busbars 57 mounted on a slate panel 58,01 other suitable means of support. Mounted on either side of and between busbars 57 are contact sprmgs'-59.- Button slots 56 have enlarged ends 60 to permit the insertion of heads 55. The other ends of slots 56 have posterior "recesse'sfil, in 'whi ch heads 55"are designedto rest and be heldiii locked engagement by 47 The arrangementjust'described is particularly adapted' to announcing systems,

where a'large number of lo1id=speal ingreceiversure operated from a master trans initting station through intermediate ampli-- fiers, and provides a simple means for replacing individual amplifiers with. a minimuminterruptio'n of the service.

"-'lfhe amplifier above described is used in am improved circuit shown in Fig. 8. Here direct current from battery 62 flows through windings 37 in series, stationary electrodesl2, granular carbon, 11, movable electrodes 17, retardation coil windings 63' and protecting resistance 64:, b-aclr to bat tcry; Wind ngs 37 are-so connected that currents-flowing therein magnetlze poles .wi'tlrlike polarity. and-pole 2,? with the opposite-polarity, whereas windi-ngs 36- are so connectedthat currents flowing therein tendto magnetize poles 35 withopposite polari- --ties; It is thus seen that alternating currents-entering windings-=36 from line conductors 65 will cause armature 2 to rock back and forth on'its fulcrum 26.

as'windi'ngs 37. are non-inductively connected with respect to windings 36 and similarly alternating or pulsating currents in windings 37 produce no rocking motion on arniature 24. The. arrangement ofthe-windings 36-and 37 'ju'stdescribed is desirable in that as,

it permits theuseof the same current to en- I g No re su-ltant current -,W1ll': be nduced n windings is that of the well-known push and pull,

or differential transmitter, wherein two transmitter buttons are customarily used and connected with a sound-receiving diaphragm, or other vibrating medium, in such a way thatan increase in the resistance of one button is accompanied by a siniiiltaneous decrease inthe resistance ofthe other. Several methods of associating such a transmitter with an output circuit are possible. One form is shown in Fig. 8, where 66 is the primary of an induction coil and 67 the secondary winding thereof, connected to outgoing line conductors 68 lhe retardatioii coil windings 63 are of high impedance and are connected inductively in series, so as to cause a minimum shunting effect on primary winding 66; Fig. 9 shows another formoi' circuit which may be used, the only difierence betweenthe circuit of Fig. 9 and the. transm tter element through the middle point of induction coil primary 66, instead of through retardation coil windings 63.

In, some classes of service to. which the amplifier of this invention is applicable,-

Where the input energy is small, there may be a tendency for the transmitter element to p2ick,'an(:l-v it has therefore been found de- 109 sirable to rovide some means for automatically' regu sting the division of current betweenthe two transmitter:buttons. Fig. I0 shows a means of accomplishing such regulation. In this case, windings 37 instead of being connected inductively in series, as in Fig. 8, are c onnectcd non-inductively in series. Current from battery 62 is led into windings 37' at their junction point 69,

through windings37 in parallehand therefore serves as in .Fig. 8 to magnetize poles 35 with like polarity. The current then flows through retardation coil windings 63 inparallel, through electrodes '17, gra 'inular carbon 11 and electrodes 12 in parallel,"

to common pointffiO, thence through rei fectingresistance 65, backto battery 62. 1A n y tendency toward inequality 'in' the "resist ance's of the two transmitter buttons will be accompanied by an inver'se difference in the current flowing therethrough, and consequently in the magnetization of the two poles 35. By connecting thedifferent elements together after the. manner shown in Fig. 10', the unequal pull on. the t-wo'eiids of the arm ature "2%, due to this inequality of niagnetir zation, may be made to expand and increase the resistance of the button of lower res-1st ance, simultaneously contract ng and l'JWGP- mg the resistance of the higher resistance having an ber therefor, and an arm operativ'ely connecting said armature with said electrode member.

8. In an electric amplifier, :1 receiver eleincnt Comprising an elcctroinagnet having a central pole and two lateral poles, an armature 'pivotally borne upon said central pole, actuating windings and magnetizing windings on said lateral poles, said magnetizing windings being non inductively connected with respect to said actuating windings, a transmitter element-in circuit with said. magnetizing windings, a vibrating electrode member for said transmitter element, and an arm operatively connecting said armature with said electrode member,

9.111. an electric amplifier, anelectromagnet, an armature therefor, a metal block with a transverse bore, two distinct carboncontaining chambers oppositely disposed and adj ustably located within. said bore and each electrode in good heat-conducting contact with the metallicwalls of said bore, a lever arm fastened to said armature and extending between said chambers, two carbon disks attached to opposite faces of said lever arm insulated therefrom and from each other and functioning as movable electrodes, for said carbon chambers.

10. In an amplifier system, an electromagnet, actuating windings and magnetizing windings for said electromagneu'said magnetizing windings being non-inductively connected ,with respcctto said actuating windings, a transmitter element, and 'a' source of, direct current serially in circuit with said transmitter element and saidmagnetizing' windings.

11. In an amplifier system, an electro magnet, actuating windings and magnetiz ing windings for said elctromagnet, a transmitter element, a source of direct current serially in circuit with. said transmitter element and said magnetizing windings, an armature for said electromagnet responsive to currents in said actuating'windings and non-responsive to transmittercurrents flowing through said magnetizing windings.

1 2.- In an amplifier systema receiver element, comprising an electromagnet, actuat:

ing' windings and a plurality of magnetizing windings therefor, said magnetizing. windins being non inducti'vely connected with respectto said actuatinglwind'ings, a diflerennet, a

-tial transmitter element comprising. a pin r'ality of transmitter buttons, and a bateircui t -with two branches, each tery supply branch including ,one; of said transmitter buttons and one of saidtmagnetizing wind- 1ngs'..

amplifier system, an electro- 13; Ii). an

armature associated with said electromagprising" a plurality *of transmitter buttons,

ture'with said movable electrodes,

' master station, a plurality "of differential transmitter element com-' a common vibrating system for said trans niitter buttons opcrativcly connected with said armature, a battery supply circuit with two brnnchr-zs, each branch including one of said transmitter .buttons and one of said magnetizing windings, said magnetizing;

and said armature, a transmitter element with two oppositely disposed electrode chambers, movable electrodes therefor, a lever arm operatively connecting said armasa-id elsetrodes being insulated from each ther and from said lever arm, and a source of direct current serially incircuitwith said magnetizing windings and said transmitter element. p

15. An amplifier system comprising a' master transmitting station, a plurality of amplifiers. having transmitter elements and receiver elements, actuating windings and magnetizing windings for said receiver elements, a source of direct current,. means for connecting said actuating windings in circuit with said master station, and othermeans for connecting said transmitter eleine'nts serially in circuit with said magnetizing windings and said source of direct current. g

.16. An amplifier system comprising a master station, busbars connected to "saidamplifiers havr ing receiver elements. and transmitter ele ments, actuating windings and magnetizing windings for said receiver elements, said:

actuatii g windings' being connected ,m a source ofdrparallel across said .busbars,

rect current, and meansfor connecting said magnetizing windingsand said-transmitter one another and with;

pli-fiers having receiver elementsand trans:

mitter elements, said receiver elements beingdetachably connected in parallel acrosssaid busbars, a source of direct current, and: resilient means for connectingfsaid transmitter elements in series with one another and with saidsource of direct current.

18. In an amplifier system, busbnrs, button slots in said busbars, a plurality of curl'Gl amplifiers, Contact buttons on said am )li ers adapted to enter into and lock in said 1ltt()11"i$l0tS,'0thel contact devices on said amplifiers, resilient means mounted adjacent to said busbnrs and adapted to make frictional contact with said contact devices and to hold said contact buttons in locked engagement with said busbars.

19. An amplifier system comprising a, lllllSCE-l transmitting station, busbarselectrically connected to the terminals of said master station, button slots in said busbnrs, a plnrzility'of current amplifiers each containing a transmitter element and a receiver element, terminal buttons for said receiver elements adapted to enter into and lock in said button slots, contact terminals for' I-LEn'RY o. EGERTON. Witnesses:

K. L. STAHL, W. F: HOFFMAN. 

